The subject of the invention is a process for the production of aluminum or magnesium phosphide by reaction of the finely divided metal or an alloy of the two metals with phosphorus.
Various agents which are used for fighting pests, especially insects and rodents contain as the effective component aluminum phosphide or magnesium phosphide. Therefore there is considerable interest in a safe and clean process for producing these phosphides.
It is known to produce various kinds of metal phosphides by melting together the metal with red phosphorus. Since the reaction between, for example, aluminum or magnesium powder and red phosphorus is strongly exothermic, it is sufficient to mix the metal powder with the red phosphorus and to bring the mixture to reaction by ignition. However, during the reaction the temperature becomes so high that a portion of the phosphorus vaporizes and burns in the air. In the case of the reaction of magnesium powder with red phosphorus explosions can even occur. The yields producible in this method of operation consequently are generally unsatisfactory.